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Optimization method for multiscale structural model of cellulose separator for lithium ion battery

A cellulose separator, lithium-ion battery technology, applied in design optimization/simulation, electrical digital data processing, material analysis using radiation diffraction, etc. Effect

Active Publication Date: 2019-10-18
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] At present, most of the research on lithium-ion separators aims to improve some aspects of the performance of the separator through modification. However, there are not many results in the study of the separator from the internal structure.

Method used

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  • Optimization method for multiscale structural model of cellulose separator for lithium ion battery
  • Optimization method for multiscale structural model of cellulose separator for lithium ion battery
  • Optimization method for multiscale structural model of cellulose separator for lithium ion battery

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Embodiment 1

[0043] Aiming at the micro-scale, the optimization method of the micro-scale structure model of the cellulose separator of lithium-ion battery includes the following steps:

[0044] S11. On the microscopic scale, the original proportion of microfibril 1 is 40%, the original proportion of matrix 2 is 60%, and the original average angle of microfibril 1 is 20 degrees. It is established that microfibril 1 is wrapped by matrix 2 The finite element model of the thin-walled cylinder, the elastic modulus E1=10.78Gpa of the model is obtained through finite element simulation;

[0045] S12. Measure the force displacement curve of a single fiber using an atomic force microscope and nanoindentation experiment method, and obtain the actual elastic modulus of a single fiber E2 = 11.71 Gpa after data processing;

[0046] S13. Compare and analyze the model elastic modulus E1 and actual elastic modulus E2, The model needs to be optimized. The proportion of the microfibrils 1 in the model can be inc...

Embodiment 2

[0051] Aiming at the mesoscale, the optimization method of the mesoscale structure model of the cellulose separator of lithium ion battery includes the following steps:

[0052] S21. Observe and obtain an environmental scanning electron microscope photo of the cellulose diaphragm at a mesoscale;

[0053] S22. Randomly select several groups of environmental scanning electron micrographs of cellulose diaphragms, use image processing methods to extract the boundary contours of the cellulose diaphragms in the photos, select one group with clear boundary contours to establish a finite element model of the cellulose diaphragm at the mesoscale, and obtain The original fiber density of the cellulose separator=60% and diameter=0.77um;

[0054] S23. Obtain the elastic modulus of the model E3=1.95Gpa through finite element simulation;

[0055] S24. Using a tensile and compressive material testing machine, using the national test standard for tensile strength of paper and cardboard (GB / T22898-200...

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Abstract

The invention discloses an optimization method for a lithium ion battery cellulose diaphragm multi-scale structural model. The method includes the steps of: S11. under a microscale, according to the original proportion of microfibril and a matrix and the original angle of microfibril, establishing a thin-walled cylindrical finite element model with the microfibril wrapped by the matrix, and conducting finite element analogue simulation to obtain an elastic modulus E1 of the model; S12. utilizing an atomic force microscope and adopting a nanoindentation experimental method to measure a force displacement curve of single fiber, and performing data processing to obtain an actual elastic modulus E2 of single fiber; S13. subjecting the elastic modulus E1 of the model and the actual elastic modulus E2 to contrastive analysis, if the result of (E1-E2) / E2 is less than -5%, increasing the proportion of the microfibril in the finite element model or decreasing the angle of the microfibril; if the result of (E1-E2) / E2 is greater than 5%, increasing the proportion of the matrix in the finite element model or increasing the angle of the microfibril; and if the result of the absolute value of (E1-E2) divided by E2 is smaller than or equal to 5%, carrying out no optimization on the finite element model. The method provided by the invention establishes and optimizes the cellulose diaphragm structural model, and improves the model accuracy.

Description

Technical field [0001] The invention relates to a lithium ion battery cellulose diaphragm technology, in particular to a method for optimizing a multi-scale structure model of a lithium ion battery cellulose diaphragm. Background technique [0002] Lithium-ion batteries have the advantages of high energy density, high working voltage, long service life, no memory effect, and green safety. They are widely used in mobile phones and other electronic products, and the new energy transportation industry represented by electric vehicles is developing rapidly . As one of the four key materials of lithium-ion batteries, the diaphragm is mainly used to isolate the positive and negative electrodes, prevent short circuits, and provide microporous channels for lithium ions to pass through. [0003] Currently, most commercial lithium ion battery separators on the market are polyolefin separators, usually unidirectional or biaxially stretched single-layer polyethylene (PE), polypropylene (PP) o...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N23/20G01Q60/24G01N3/08G01N23/2251G06F17/50
CPCG01N3/08G01N23/20G01N23/22G01Q60/24G06F30/23
Inventor 彭羽健刘旺玉谢卫规闫长媛党艳萍
Owner SOUTH CHINA UNIV OF TECH